Acquired thrombocytopenia after transcatheter aortic valve replacement: clinical correlates and association with outcomes

Subclinical leaflet thrombus in patients with severe aortic stenosis and atrial fibrillation -ENRICH-AF TAVI study

Subclinical leaflet thrombosis (SLT) can be one of the causes of transcatheter heart valve (THV) failure after transcatheter aortic valve implantation (TAVI). We sought to clarify the formation process of SLT and thrombogenicity during the perioperative period of TAVI. This multicenter, prospective, single-arm interventional study enrolled 26 patients treated with edoxaban for atrial fibrillation and who underwent TAVI for severe aortic stenosis between September 2018 and September 2022. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI in 18 patients and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD) (n = 11). SLT was observed in 16.7% (3/18) at 1 week, but decreased to 5.9% (1/17) at 3 months after TAVI. Patients with SLT at 1 week had a significantly decreased maximal leaflet thickness compared to those without SLT. Thrombogenicity assessed by T-TAS decreased markedly at 1 week and tended to increase at 3 months. The stagnation volume assessed by CFD was positively associated with a higher maximum leaflet thickness. This study showed the course of leaflet thrombus formation and visualization of stagnation in neo-sinus of THV in the acute phase after TAVI.

Thrombocytopenia Following Perceval Sutureless Aortic Valve Replacement in Asian Patients

BACKGROUND

This study analyzed the safety and performance of the Perceval valve for aortic valve replacement (AVR) in patients at 1 year after undergoing aortic stenosis (AS) treatment, and its effect on significant declines in the platelet count during the immediate postoperative period.Methods and Results: Data were collected retrospectively for the initial 121 patients (median age 77 years; 47.1% females) who underwent Perceval sutureless AVR between May 2019 and July 2022. Implantation was successful in all (100%), with median cross-clamp and CPB times of 59 and 100 min, respectively. Postoperative thrombocytopenia (platelet count <50×103/μL) was noted in 80 (66.1%) patients. Multivariate analysis showed advanced age (>80 years), preoperative low platelet count (<200×103/μL), and a sternotomy approach as significant risk factors for postoperative thrombocytopenia. One (0.8%) patient died within 30 days after the procedure. The 2-year site-reported event rate was 14% (n=17) for all-cause mortality, 0.8% (n=1) for cardiac mortality, 4.1% (n=5) for stroke, and 1.7% (n=2) for endocarditis and valve-related reoperation; there were no instances of paravalvular leakage or structural valve deterioration.

CONCLUSIONS

Thrombocytopenia was common after Perceval sutureless AVR, although its impact was not significant. Although Perceval sutureless AVR was found to be a safe and effective option, preoperative assessment of potential bleeding should be performed and the Perceval valve should not be used for patients with a high bleeding risk.

Acquired Thrombocytopenia in Contemporary Transcatheter Aortic Valve Prosthesis

BACKGROUND

 Postprocedural thrombocytopenia is a known phenomenon following transcatheter aortic valve implantation (TAVI). The aim of this study is to evaluate whether postinterventional platelet kinetics differ when comparing the current generation of balloon-expandable valve (BEV) and self-expanding valve (SEV) prostheses.

METHODS

 We performed a retrospective analysis of patients undergoing TAVI at our facility between 2017 and 2019. Patients were stratified according to the type of prosthesis used: BEV or SEV. Hematocrit-corrected platelet counts were calculated to account for dilution. Nadir platelet counts (lowest recorded platelet count), drop platelet counts (DPC; highest relative platelet drop from baseline), and severity of thrombocytopenia during the discourse and at discharge were assessed.

RESULTS

 Of the 277 included patients, 212 received SEV and 65 BEV. BEV patients were younger (81.8 ± 4.4 years vs 79.7 ± 6.8 years, p = 0.03). Further demographic characteristics were similar between groups. Implanted SEV were larger (p < 0.001) and had shorter procedural times (p < 0.01). There were no significant differences in postprocedural discourse. Postinterventional platelet drop was more pronounced in BEV patients in several evaluated metrics: mean DPC (24.3 ± 10.9% vs 18.8 ± 14.8%, p < 0.01), patients with DPC > 30% (n = 19, 29.2%, vs n = 33, 15.6%, p = 0.02), and also when comparing platelet kinetics.

CONCLUSION

 Despite improvements in outcome, the current generation of balloon-expandable TAVI prostheses carries a predisposition for postprocedural thrombocytopenia even when the effects of dilution are accounted for.

Antithrombotic Management for Transcatheter Aortic Valve Implantation

BACKGROUND

There have been significant changes in the optimal antithrombotic regimen post transcatheter aortic valve implantation (TAVI) after the results of major clinical trials in the past few years. Given the clinical importance of the optimal antithrombotic therapy post TAVI, we performed a narrative description of the major clinical trials behind the scientific evidence supporting these changes, as well the current guideline recommendations and knowledge gaps.

METHODS

We performed a narrative description of the major clinical trials behind the scientific evidence supporting these changes. We used PubMed as a major source to collect the major clinical trials including the following key words: "transcatheter aortic valve replacement", "transcatheter aortic valve implantation", "antithrombotic", "antiplatelet" and "anticoagulation". We selected the major clinical trials on this topic. This is not a systematic review or meta-analysis.

RESULTS

We describe the results of the major clinical trials on antithrombotic therapy post TAVI: POPULAR-TAVI A, POPULAR-TAVI B, ENVISAGE-TAVI AF, GALILEO, ATLANTIS and ADAPT-TAVR trials. Based on the results of these trials, single antiplatelet therapy is recommended post TAVI in patients without concomitant indication for oral anticoagulation or dual antiplatelet therapy, especially in elderly patients. In younger patients, it is advised to evaluate the patient's bleeding and thrombotic risk, and dual antiplatelet therapy may be reasonable in patients with a high thrombotic risk and low bleeding risk. In patients with a concurrent indication for oral anticoagulation or dual antiplatelet therapy, it is recommended to continue oral anticoagulation or dual antiplatelet therapy post TAVI.

CONCLUSION

In most patients without concomitant indication for oral anticoagulation, single antiplatelet therapy is recommended post TAVI.

Is dynamic change in mean platelet volume related with composite endpoint development after transcatheter aortic valve replacement?

Aortic valve stenosis (AS) is the most common valvular disease, and surgical or transcatheter aortic valve replacement (TAVR) are the treatment options. Diminish in platelet production or dysfunction may occur due to shear stress, advanced age, and other coexisting diseases in AS patients. Bleeding is one of the complications of TAVR and associated with increased mortality. MPV (mean platelet volume) indicates platelet's thrombogenic activity. Overproduction or consumption of platelets in various cardiac conditions may affect MPV values. We aimed to investigate the pre and postprocedure MPV percentage change (MPV-PC) and its association with post-TAVR short-term complications. A total of 204 patients who underwent TAVR with a diagnosis of severe symptomatic AS were included. The mean age was 78.66 ± 6.45 years, and 49.5% of patients were women. Two groups generated according to composite end point (CEP) development: CEP(+) and CEP(-).110 patients(53.9%) formed CEP(+) group. Although baseline MPV and platelet levels were similar between groups, MPV was increased ( P  < 0.001) and platelet was decreased ( P  < 0.001) significantly following the procedure when compared to baseline. MPV-PC was significantly higher in the VARC type 2-4 bleeding ( P   =  0.036) and major vascular, access-related, or cardiac structural complication groups ( P   =  0.048) when CEP subgroups were analyzed individually. Regression analysis revealed that diabetes mellitus [ P   =  0.044, β: 1.806 odds ratio (95% confidence interval): 1.016-3.21] and MPV-PC [ P   =  0.007,β: 1.044 odds ratio (95% confidence interval): 1.012-1.077] as independent predictors of CEP development at 1 month after TAVR. The MPV increase following TAVR may be an indicator of adverse outcomes following TAVR procedure within 1-month.

Restoration of von Willebrand factor after transcatheter aortic valve replacement-A possible cause for posttranscatheter aortic valve replacement thrombocytopenia?

OBJECTIVES

The aim of the current study was to analyze the clinical and procedural predictors of thrombocytopenia and the relationship between the decrease in platelet count (DPC) and change in vWF function (ΔvWF) after transcatheter aortic valve replacement (TAVR).

BACKGROUND

TAVR often causes temporary thrombocytopenia. At the same time, TAVR leads to a restoration of von Willebrand factor (vWF) function.

METHODS

One hundred and forty-one patients with severe aortic stenosis undergoing TAVR were included in the study. Platelet count and vWF function (vWF:Ac/Ag ratio) were assessed at baseline and 6 h after TAVR. Thrombocytopenia was defined as platelet count <150/nL.

RESULTS

Median platelet count at baseline was 214/nL (interquartile range [IQR]: 176-261) and decreased significantly to 184/nL (IQR: 145-222) 6 h after TAVR. The number of patients with thrombocytopenia increased from 12.8% at baseline to 29.1% after 6 h. DPC 6 h after TAVR showed a significant correlation with ΔvWF (r = - 0.254, p = 0.002). Patients with DPC > 20% had significantly higher ΔvWF (10.9% vs. 6.5%, p = 0.021). Obese patients showed a significantly lower DPC (11.8% vs. 19.9%, p = 0.001). In multivariate analysis, ΔvWF 6 h after TAVR was the only significant predictor for DPC > 20% (p = 0.017).

CONCLUSIONS

The restoration of vWF after TAVR is a significant predictor for DPC after TAVR. An increased platelet consumption due to vWF restoration could play a key role in the development of thrombocytopenia after TAVR.

PEAL Score to Predict the Mortality Risk of Cardiogenic Shock in the Emergency Department: An Observational Study

BACKGROUND

The in-hospital mortality of cardiogenic shock (CS) remains high (28% to 45%). As a result, several studies developed prediction models to assess the mortality risk and provide guidance on treatment, including CardShock and IABP-SHOCK II scores, which performed modestly in external validation studies, reflecting the heterogeneity of the CS populations. Few articles established predictive scores of CS based on Asian people with a higher burden of comorbidities than Caucasians. We aimed to describe the clinical characteristics of a contemporary Asian population with CS, identify risk factors, and develop a predictive scoring model.

METHODS

A retrospective observational study was conducted between 2014 and 2019 to collect the patients who presented with all-cause CS in the emergency department of a single medical center in Taiwan. We divided patients into subgroups of CS related to acute myocardial infarction (AMI-CS) or heart failure (HF-CS). The outcome was all-cause 30-day mortality. We built the prediction model based on the hazard ratio of significant variables, and the cutoff point of each predictor was determined using the Youden index. We also assessed the discrimination ability of the risk score using the area under a receiver operating characteristic curve.

RESULTS

We enrolled 225 patients with CS. One hundred and seven patients (47.6%) were due to AMI-CS, and ninety-eight patients among them received reperfusion therapy. Forty-nine patients (21.8%) eventually died within 30 days. Fifty-three patients (23.55%) presented with platelet counts < 155 × 103/μL, which were negatively associated with a 30-day mortality of CS in the restrictive cubic spline plot, even within the normal range of platelet counts. We identified four predictors: platelet counts < 200 × 103/μL (HR 2.574, 95% CI 1.379-4.805, p = 0.003), left ventricular ejection fraction (LVEF) < 40% (HR 2.613, 95% CI 1.020-6.692, p = 0.045), age > 71 years (HR 2.452, 95% CI 1.327-4.531, p = 0.004), and lactate > 2.7 mmol/L (HR 1.967, 95% CI 1.069-3.620, p = 0.030). The risk score ended with a maximum of 5 points and showed an AUC (95% CI) of 0.774 (0.705-0.843) for all patients, 0.781 (0.678-0.883), and 0.759 (0.662-0.855) for AMI-CS and HF-CS sub-groups, respectively, all p < 0.001.

CONCLUSIONS

Based on four parameters, platelet counts, LVEF, age, and lactate (PEAL), this model showed a good predictive performance for all-cause mortality at 30 days in the all patients, AMI-CS, and HF-CS subgroups. The restrictive cubic spline plot showed a significantly negative correlation between initial platelet counts and 30-day mortality risk in the AMI-CS and HF-CS subgroups.

Transcatheter aortic valve intervention in patients with cancer

The prevalence of concurrent cancer and severe aortic stenosis (AS) is increasing due to an ageing population. In addition to shared traditional risk factors for AS and cancer, patients with cancer may be at increased risk for AS due to off-target effects of cancer-related therapy, such as mediastinal radiation therapy (XRT), as well as shared non-traditional pathophysiological mechanisms. Compared with surgical aortic valve replacement, major adverse events are generally lower in patients with cancer undergoing transcatheter aortic valve intervention (TAVI), especially in those with history of mediastinal XRT. Similar procedural and short-to-intermediate TAVI outcomes have been observed in patients with cancer as compared with no cancer, whereas long-term outcomes are dependent on cancer survival. Considerable heterogeneity exists between cancer subtypes and stage, with worse outcomes observed in those with active and advanced-stage disease as well as specific cancer subtypes. Procedural management in patients with cancer poses unique challenges and thus requires periprocedural expertise and close collaboration with the referring oncology team. The decision to ultimately pursue TAVI involves a multidisciplinary and holistic approach in assessing the appropriateness of intervention. Further clinical trial and registry studies are needed to better appreciate outcomes in this population.

Predictive model for severe thrombocytopenia after transfemoral transcatheter aortic valve replacement

The aim of this study was to develop a predictive model for severe thrombocytopenia after transfemoral transcatheter aortic valve replacement (TAVR). A total of 155 patients treated with TAVR at our center were retrospectively enrolled in this study. The incidence of severe thrombocytopenia after TAVR was 25.16%, and most patients suffered from severe thrombocytopenia on 4 days after procedure. Multivariate regression analysis showed that weight <60 kg, New York Heart Association Functional Classification (NYHAFC IV), major vascular complications, and lower first post-procedural platelet count were independent risk factors for severe thrombocytopenia after TAVR. The c-statistic for the area under the curve was 0.758, the sensitivity was 0.744, the specificity was 0.784, and the negative predictive value of the model was 91.38%. The overall predictive value was 76.77%. The predictive model developed from this cohort data could effectively identify patients at high risk of severe thrombocytopenia after TAVR, and might be applicable to patients with aortic regurgitation (AR) and severe thrombocytopenia with different definitions.

Bleeding Events After Transcatheter Aortic Valve Replacement: JACC State-of-the-Art Review

Transcatheter aortic valve replacement (TAVR) has gained over time a major reduction in procedural complications. Despite this, clinically relevant bleeding still occurs in a non-negligible proportion of patients and adversely affects prognosis. Patients with severe aortic stenosis are at heightened risk for spontaneous bleeding due to advanced age and a high comorbidity burden. Also, procedural factors and antithrombotic management contribute to define individual bleeding susceptibility. Bleeding prevention represents an emerging area for improving patient care. Because of the tight hemorrhagic/ischemic balance, a tailored approach based on individual bleeding-risk profile, such as a less invasive antithrombotic regimen or appropriate diagnostic preprocedural evaluation, should be pursued to avoid bleeding events. This review aims to provide an in-depth overview of bleeding events in the TAVR field, including definitions, timing and the extent of risk, and clinical impact, as well as updates on antithrombotic management and its potential influence on bleeding complications.

A New Definition of Thrombocytopenia Following Transcatheter Aortic Valve Implantation: Incidence, Outcome, and Predictors

Background: The aim of this study was to assess the incidence, outcomes, and risk factors associated with thrombocytopenia following TAVI according to a corrected platelet count (CPC), to avoid the bias of hemodilution/concentration. Methods: We analyzed patients who underwent TAVI in our center between 2009 and 2018. The study population were divided into three groups: none (NT), mild (MT), and severe (ST) postoperative thrombocytopenia. Primary outcomes were bleedings, length of hospital stay, and mortality. A multivariate logistic regression was performed to assess risk factors for ST. Results: A total of 907 patients were included in the analysis. MT was observed in 28.1% and ST in 2.6% of all patients. The following clinical outcomes were recorded: incidence of life-threatening and major bleeding (NT = 14.2%, MT = 20.8%, ST = 58.3%), the median length of hospital stay (NT = 8, MT = 10, ST = 14 days), in-hospital mortality (NT = 3.9%, MT = 6.3%, ST = 16.7%), and the overall significance in comparison with NT (p < 0.05). The logistic regression showed ST was associated with preoperative CPC, transapical access, diabetes mellitus, and the critical preoperative state. Conclusions: Worse clinical outcomes are associated with both MT and ST after TAVI. In particular, ST is associated with higher in-hospital and 30-day mortality. Management of modifiable baseline and procedural variables may improve this outcome.

Machine Learning-Based Personalized Risk Prediction Model for Mortality of Patients Undergoing Mitral Valve Surgery: The PRIME Score

Background

Mitral valve surgery (MVS) is an effective treatment for mitral valve diseases. There is a lack of reliable personalized risk prediction models for mortality in patients undergoing mitral valve surgery. Our aim was to develop a risk stratification system to predict all-cause mortality in patients after mitral valve surgery.

Methods

Different machine learning models for the prediction of all-cause mortality were trained on a derivation cohort of 1,883 patients undergoing mitral valve surgery [split into a training cohort (70%) and internal validation cohort (30%)] to predict all-cause mortality. Forty-five clinical variables routinely evaluated at discharge were used to train the models. The best performance model (PRIME score) was tested in an externally validated cohort of 220 patients undergoing mitral valve surgery. The model performance was evaluated according to the area under the curve (AUC). Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were compared with existing risk strategies.

Results

After a median follow-up of 2 years, there were 133 (7.063%) deaths in the derivation cohort and 17 (7.727%) deaths in the validation cohort. The PRIME score showed an AUC of 0.902 (95% confidence interval [CI], 0.849–0.956) in the internal validation cohort and 0.873 (95% CI: 0.769–0.977) in the external validation cohort. In the external validation cohort, the performance of the PRIME score was significantly improved compared with that of the existing EuroSCORE II (NRI = 0.550, [95% CI 0.001–1.099], P = 0.049, IDI = 0.485, [95% CI 0.230–0.741], P < 0.001).

Conclusion

Machine learning-based model (the PRIME score) that integrate clinical, demographic, imaging, and laboratory features demonstrated superior performance for the prediction of mortality patients after mitral valve surgery compared with the traditional risk model EuroSCORE II.

Clinical Trial Registration

[http://www.clinicaltrials.gov], identifier [NCT05141292].

Trends in Transfemoral Aortic Valve Implantation Related Thrombocytopenia

Background: TAVI related thrombocytopenia (TAVI-rTP) is still very common. The aim of this study was to compare the incidence, characteristics and impact of reduced platelet counts (RPC) after TAVI between an earlier and contemporary period. Methods: the patients enrolled were those experiencing severe symptomatic aortic stenosis who underwent TAVI between January 2010 and December 2019. The exclusion criteria were no available blood tests and periprocedural death. Results: 334 patients (mean age 81.9 ± 6.7 years) were enrolled. For the earlier period, the mean RPC was 33 ± 15%, and in the contemporary period (2016–2019) it was 26 ± 14%. In the early group, we found that 62% of the patients had decreased platelet counts of more or equal to 30% in comparison to 33% in the contemporary period. The time of the procedure and the amount of the contrast that had been used in the later period were associated with significant RPCs (p value = 0.002 and 0.028, respectively). An RPC of 30% or more was associated with the increased risks of life-threatening bleeding, vascular complications and death within 30 days. Conclusion: contemporary TAVI-rTP continued to be a common phenomenon in our cohort. However, severe thrombocytopenia was significantly less frequent. An RPC of 30% or more is associated with a poor 30-day outcome.

Baseline mean platelet volume is a strong predictor of major and life-threatening bleedings after transcatheter aortic valve replacement

BACKGROUND

Bleeding following transcatheter aortic valve replacement (TAVR) has important prognostic implications. This study sought to evaluate the impact of baseline mean platelet volume (MPV) on bleeding events after TAVR.

METHODS AND RESULTS

Patients undergoing TAVR between February 2010 and May 2019 were included. Low MPV (L-MPV) was defined as MPV ≤10 fL and high MPV (H-MPV) as MPV >10 fL. The primary endpoint was the occurrence of major/life-threatening bleeding complications (MLBCs) at one-year follow-up. Among 1,111 patients, 398 (35.8%) had L-MPV and 713 (64.2%) had H-MPV. The rate of MLBCs at 1 year was higher in L-MPV patients compared with H-MPV patients (22.9% vs. 17.7% respectively, p = 0.034). L-MPV was associated with vascular access-site complications (36.2% vs. 28.9%, p = 0.012), early (<30 days) major bleeding (15.6% vs. 9.4%, p<0.01) and red blood cell transfusion >2 units (23.9% vs. 17.5%, p = 0.01). No impact of baseline MPV on overall death, cardiovascular death and ischemic events (myocardial infarction and stroke) was evidenced. Multivariate analysis using Fine and Gray model identified preprocedural hemoglobin (sHR 0.84, 95%CI [0.75-0.93], p = 0.001), preprocedural L-MPV (sHR 1.64, 95%CI [1.16-2.32], p = 0.005) and closure time adenosine diphosphate post-TAVR (sHR 2.71, 95%CI [1.87-3.95], p<0.001) as predictors of MLBCs.

CONCLUSIONS

Preprocedural MPV was identified as an independent predictor of MLBCs one year after TAVR, regardless of the extent of platelet inhibition and primary hemostasis disorders.

Spleen Size and Thrombocytopenia After Transcatheter Aortic Valve Implantation

The pathophysiology of thrombocytopenia after transcatheter aortic valve implantation (TAVI) thrombocytopenia is still poorly understood. We assessed the association of spleen size with acquired thrombocytopenia in patients undergoing TAVI. We included 732 patients who underwent TAVI with new generation transcatheter heart valves (THVs) at our center from February 2016 to July 2019. We measured splenic volume index in consecutive patients derived from multidetector row computed tomographic datasets. Patients were stratified according to post-TAVI thrombocytopenia, which was defined as a decline in platelet count (DPC) ≥50% at nadir, and evaluated regarding baseline characteristics and outcome parameters. After the procedure, platelet counts declined from 212.9 ± 67.4 × 10⁹/L at baseline to 138.8 ± 49.8 × 10⁹/L at nadir after a median of 2 days (interquartile range [IQR] 2 to 3). Of all patients, 10.1% showed a DPC ≥50%. Compared with patients with DPC <50%, patients with DPC ≥50% had significantly lower splenic volume index (95.5 ml/m² [IQR 78.0 to 123.7] vs 85.8 ml/m² [IQR 71.4 to 102.6], p = 0.008). A multivariable analysis revealed that the splenic volume index was negatively associated with a DPC ≥50% (OR 0.89, 95% CI 0.82 to 0.97, p = 0.005), independent of the type of THV (balloon-expandable THV: OR 2.06, 95% CI 1.13 to 3.76, p = 0.02), major bleeding (OR 13.40, 95% CI 3.58 to 50.40, p <0.001), blood transfusion (OR 3.63, 95% CI 1.54 to 8.56, p = 0.003), or postprocedural paravalvular leakage ≥moderate (OR 5.48, 95% CI 1.23 to 24.40, p = 0.03). Furthermore, DPC ≥50% was independently associated with 1-year mortality (HR 3.36, 95% CI 1.66 to 6.81, p <0.001). In conclusion, acquired thrombocytopenia remains prevalent in modern TAVI patients. Spleen size appears to be associated with the occurrence of thrombocytopenia after TAVI, which is independently correlated with 1-year mortality.

Using Machine Learning Algorithms to Predict Hospital Acquired Thrombocytopenia after Operation in the Intensive Care Unit: A Retrospective Cohort Study

Hospital acquired thrombocytopenia (HAT) is a common hematological complication after surgery. This research aimed to develop and compare the performance of seven machine learning (ML) algorithms for predicting patients that are at risk of HAT after surgery. We conducted a retrospective cohort study which enrolled adult patients transferred to the intensive care unit (ICU) after surgery in West China Hospital of Sichuan University from January 2016 to December 2018. All subjects were randomly divided into a derivation set (70%) and test set (30%). ten-fold cross-validation was used to estimate the hyperparameters of ML algorithms during the training process in the derivation set. After ML models were developed, the sensitivity, specificity, area under the curve (AUC), and net benefit (decision analysis curve, DCA) were calculated to evaluate the performances of ML models in the test set. A total of 10,369 patients were included and in 1354 (13.1%) HAT occurred. The AUC of all seven ML models exceeded 0.7, the two highest were Gradient Boosting (GB) (0.834, 0.814-0.853, p < 0.001) and Random Forest (RF) (0.828, 0.807-0.848, p < 0.001). There was no difference between GB and RF (0.834 vs. 0.828, p = 0.293); however, these two were better than the remaining five models (p < 0.001). The DCA revealed that all ML models had high net benefits with a threshold probability approximately less than 0.6. In conclusion, we found that ML models constructed by multiple preoperative variables can predict HAT in patients transferred to ICU after surgery, which can improve risk stratification and guide management in clinical practice.

Contemporary transcatheter aortic valve implantation related thrombocytopenia

BACKGROUND

Transcatheter aortic valve implantation related thrombocytopenia (TAVI-rTP) is an inevitable phenomenon. However, no study has been performed on TAVI-rTP in the current setting of extended clinical indications combined with technology improvements.

METHODS

Patients with severe symptomatic aortic stenosis who underwent transfemoral TAVI, from January 2016 to December 2019 were enrolled.

RESULTS

Two-hundred and one consecutive patients (mean age 81.1 ± 7.1 years, 96 men) enrolled. Platelet count was recorded before and after aortic valve implantation. Dropped platelet count (DPC) occurred in all but 11 patients who were included. Two groups were created: DPC <30 and DPC ≥30%. DPC was compared with in-hospital major adverse cardiovascular events. The mean DPC was 26 ± 14%. We found that 67 patients (33.3%) had DPC of more or equal to 30%. In the univariable analysis, the time of the procedure (94.4 ± 32.7 vs 79.4 ± 21.9, p = .002), the amount of the contrast used (125.4 ± 55.4 vs 108.4 ± 44.1, p = .02) and the residual AV gradient (13.3 ± 7.2 vs 14.7, p = .05) were related to a DCP ≥30%. A DPC ≥30% was associated with increased risk of life-threatening/major bleeding (11.9% vs 1.5%, p = .001), major vascular complications (16.4% vs 5.2% p = .009) and death (3.0% vs 0%, p = .044) at 30 days. After multivariable analysis, the factors associated with a higher DPC were time and contrast.

CONCLUSION

Contemporary TAVI-rTP in this cohort of patients continues to be a common phenomenon but severe thrombocytopenia is less frequent. Patients developing a DPC ≥30% are associated with poor outcomes at 30 days.

Antithrombotic therapy in patients undergoing transcatheter aortic valve replacement: the complexity of the elderly

Along with epidemiologic transitions of the global population, the burden of aortic stenosis (AS) is rapidly increasing and transcatheter aortic valve replacement (TAVR) has quickly spread; indeed, it is nowadays also employed in treating patients with AS at intermediate operative risk. Nonetheless, the less invasive interventional strategy still carries relevant issues concerning post-procedural optimal antithrombotic strategy, given the current indications provided by guidelines are not completely supported by evidence-based data. Geriatric patients suffer from high bleeding and thromboembolic risks, whose balance is particularly subtle due to the presence of concomitant conditions, such as atrial fibrillation and chronic kidney disease, that make the post-TAVR antithrombotic management particularly insidious. This scenario is further complicated by the lack of specific evidence regarding the 'real-life' complex conditions typical of the geriatric syndromes, thus, the management of such a heterogeneous population, ranging from healthy ageing to frailty, is far from being defined. The aim of the present review is to summarize the critical points and the most updated evidence regarding the post-TAVR antithrombotic approach in the geriatric population, with a specific focus on the most frequent clinical settings.

Thrombocytopenia Complicating Transcatheter Aortic Valve Implantation: Differences Between Two New-Generation Devices

Thrombocytopenia after TAVI is common and clinically detrimental. Retrospectively, we observed Portico recipients had a more profound platelet drop than Evolut recipients. We thus investigated periprocedural platelet damage and/orpro-inflammatory state in 64 TAVI recipients at baseline and after implantation. Platelet damage was assessed by annexin V staining and monocyte-phagocytic phenotype was assessed according to CD14/CD36 expression. Serum cytokines were measured in 20 patients. The formaldehyde-based storage solution altered platelets. When, before being loaded onto the delivery system, Portico underwent one additional flushing to those recommended, the receiving patients showed thrombocytopenia, platelet damage, and CD36-monocyte count were mitigated. A general increase in IL-6 was recorded in overall TAVI recipients, but a high serum level of IL-8, a potent thrombocytopenia inducer, was measured in Portico recipients only, including those with extra-rinsed valve. Our study suggests a platelet-injury effect by storage-solution and generates the hypothesis of a role for the biomaterial in stimulating innate-immunity. Larger prospective studies are needed.

Quantitative and Qualitative Platelet Derangements in Cardiac Surgery and Extracorporeal Life Support

Thrombocytopenia and impaired platelet function are known as intrinsic drawbacks of cardiac surgery and extracorporeal life supports (ECLS). A number of different factors influence platelet count and function including the inflammatory response to a cardiopulmonary bypass (CPB) or to ECLS, hemodilution, hypothermia, mechanical damage and preoperative treatment with platelet-inhibiting agents. Moreover, although underestimated, heparin-induced thrombocytopenia is still a hiccup in the perioperative management of cardiac surgical and, above all, ECLS patients. Moreover, recent investigations have highlighted how platelet disorders also affect patients undergoing biological prosthesis implantation. Though many hypotheses have been suggested, the mechanism underlying thrombocytopenia and platelet disorders is still to be cleared. This narrative review aims to offer clinicians a summary of their major causes in the cardiac surgery setting.

Association between platelet counts and morbidity and mortality after endovascular repair for type B aortic dissection

This study aimed to assess the association of postoperative platelet counts with early and late outcomes after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We retrospectively evaluated 892 patients with TBAD who underwent TEVAR from a prospectively maintained database. Postoperative nadir platelet counts were evaluated as a continuous variable, and a categorical variable (thrombocytopenia), which was defined as platelet count≤ the lowest 10% percentile (108 × 10⁹/l). Multivariable logistic regression analyses were conducted to assess the impact of postoperative thrombocytopenia on early outcomes, and multivariable cox regression analyses on long-term mortality. Patients with postoperative thrombocytopenia experienced significantly higher rates of postoperative mortality, prolonged intensive care unit stay, death, stroke, limb ischemia, mesenteric ischemia, acute kidney injury (AKI), and puncture-related hematoma (P< .05 for each), but similar rates of immediate type I endoleak and spinal cord ischemia. Multivariable logistic analyses showed that postoperative thrombocytopenia was independently associated with postoperative stroke, limb ischemia, and AKI. Similar results were observed when postoperative nadir platelet count was modeled as a continuous predictor (P< .05 for each). By multivariable Cox analyses, postoperative thrombocytopenia was an independent predictor for long-term all-cause mortality (hazard ratio 2.72, 95% CI, 1.72-4.29, P< .001). For every 30 × 10⁹/L decrease in postoperative platelet count, the risk of long-term all-cause mortality increased by 15% (HR 1.15; 95% CI 1.07-1.25; P< .001). Therefore, postoperative thrombocytopenia might be a useful tool for risk stratification after TEVAR.

Predictors of short-term thrombocytopenia after transcatheter aortic valve implantation: a retrospective study at a single Japanese center

OBJECTIVE

Thrombocytopenia is common after transcatheter aortic valve implantation (TAVI) and is associated with mortality and major complications, although the underlying mechanisms are unclear. This retrospective single-center study aimed to identify factors associated with the decrease in platelet count (DPC) after TAVI in Japanese patients. Patients with severe aortic valve stenosis who underwent transfemoral TAVI between March 2014 and August 2019 were grouped according to DPC values of < 50% or ≥ 50% (DPC = 100% × [baseline platelet count-nadir platelet count]/[baseline platelet count]). Multivariable logistic regression analysis was performed to identify factors associated with a DPC of ≥ 50%.

RESULTS

Among the 131 patients who underwent transfemoral TAVI, 74 patients (56%) had a DPC of ≥ 50%, and 57 patients (44%) had a DPC of < 50%. Significant risk factors for a DPC of ≥ 50% were older age, lower body mass index (BMI), and use of balloon-expandable valves (BEV). The multivariable analysis revealed that a DPC of ≥ 50% was independently predicted by low BMI (adjusted odds ratio: 0.884, 95% confidence interval: 0.785-0.997; P = 0.039) and BEV use (adjusted odds ratio: 3.014, 95% confidence interval: 1.003-9.056; P = 0.045). Platelet count monitoring after TAVI, especially when using BEV devices, is essential for Japanese patients with low BMI.

Impact of postprocedural thrombocytopenia on mortality after transcatheter aortic valve implantation

AIMS

We performed a meta-analysis of currently available studies investigating the impact of postprocedural thrombocytopenia on mortality after transcatheter aortic valve implantation (TAVI).

METHODS

All studies researching the impact of postprocedural thrombocytopenia on mortality after TAVI were identified after searching PubMed and Web of Science through July 2019. The outcome of interest was early (in-hospital or 30-day) and overall (1- to 2-year) all-cause mortality after TAVI. From each study, the number of deaths in both patients with major (moderate/severe or higher postprocedural drop platelet counts defined in each study) and nonmajor (no/minor or lower drop platelet counts defined in each study) postprocedural thrombocytopenia was extracted. Then, odds ratios (ORs) of mortality for major vs. no/minor thrombocytopenia and their confidence intervals were generated. Alternatively, ORs and hazard ratios of mortality for major vs. no/minor thrombocytopenia (if available, adjusted) were directly extracted. Study-specific estimates were pooled in both the fixed-effect and random-effects models.

RESULTS

The principal pooled analysis demonstrated that postprocedural thrombocytopenia was associated with statistically significant increases in early (OR, 3.79; P for effect <0.00001; P for heterogeneity = 0.89) and overall mortality (OR/hazard ratio, 1.22; P for effect = 0.009; P for heterogeneity = 0.17) in the fixed-effect model. All sensitivity analyses did not substantively alter the results of the principal analysis. No funnel plot asymmetry of the principal analysis was detected (P for early mortality = 0.88; P for overall mortality = 0.14), which suggested probably no publication bias.

CONCLUSION

Postprocedural thrombocytopenia is associated with increased early and overall mortality after TAVI.

Evaluation of Acquired Thrombocytopenia According to the Balloon-Expandable Versus Self-Expandable Valves in Patients Undergoing Transcatheter Aortic Valve Replacement

In patients with severe aortic stenosis, the data about the incidence of acquired thrombocytopenia according to the use of balloon-expandable or self-expandable valves are limited. We investigated the relationship between the post-transcatheter aortic valve replacement (TAVR) thrombocytopenia and the balloon-expandable or self-expandable valves. A total of 127 consecutive patients who underwent TAVR were retrospectively analyzed. Among the study population, 61 (48%) patients underwent TAVR with the balloon-expandable valve and the 66 (52%) patients with the self-expandable valve. Procedural success did not differ between the groups (P = .575). The access site complications and in-hospital mortality were the same across the groups (P = .225 and P = .466). However, paravalvular (PV) leaks were significantly higher in the self-expandable valve group (P = .007). Among all, 65 patients experienced thrombocytopenia, which was more frequent in the self-expandable valve group (63.6 vs 37.7%, P = .005). In multivariate analyses, admission platelet count, PV leak, and self-expandable valve deployment were the predictors of thrombocytopenia (P = .001, P = .002, and P = .021, respectively). The present study showed a higher incidence of acquired thrombocytopenia in the self-expandable valve group. Although the procedural success was similar between the groups, postprocedural PV leaks were more common in the self-expandable valve group.

TAVR patients count on their thrombocytes: Platelets count is accountable for the outcomes!

Chronic thrombocytopenia is frequent in patients undergoing TAVR in the real world. Chronic thrombocytopenia is associated with worse in-hospital outcomes after TAVR. Future research is necessary to establish a better way of conducting and monitoring these patients.

Measuring beta-galactose exposure on platelets: Standardization and healthy reference values

BACKGROUND

Correct diagnosis of the cause of thrombocytopenia is crucial for the appropriate management of patients. Hyposialylation/desialylation (characterized by abnormally high β-galactose exposure) accelerates platelet clearance and can lead to thrombocytopenia. However, the reference range for β-galactose exposure in healthy individuals has not been defined previously.

OBJECTIVE

The objective of the present study was to develop a standardized assay of platelet β-galactose exposure for implementation in a clinical laboratory.

METHODS

β-Galactose exposure was measured in platelet-rich plasma by using flow cytometry and Ricinus communis agglutinin (RCA). A population of 120 healthy adults was recruited to study variability.

RESULTS

We determined an optimal RCA concentration of 12.5 μg/mL. The measure was stable for up to 4 hours (mean fluorescence intensity [MFI]-RCA: 1233 ± 329 at 0 hour and 1480 ± 410 at 4 hours). The platelet count did not induce a variation of RCA and the measure of RCA was stable when tested up to 24 hours after blood collection (MFI-RCA: 1252 ± 434 at day 0 and 1140 ± 297 24 hours after blood sampling). To take into account the platelet size, results should be expressed as RCA/forward scatter ratio. We used the assay to study variability in 120 healthy adults, and we found that the ratio is independent of sex and blood group.

CONCLUSION

We defined a normal range in a healthy population and several preanalytical and analytical variables were evaluated, together with positive and negative controls. This assay may assist in the diagnosis of thrombocytopenic diseases linked to changes in β-galactose exposure.

Predictor and Mid-Term Outcome of Clinically Significant Thrombocytopenia After Transcatheter Aortic Valve Selection

BACKGROUND

The frequency and predictors of thrombocytopenia after transcatheter aortic valve implantation (TAVI) are unclear.Methods and Results:This study enrolled 342 patients undergoing TAVI (245 with a percutaneous transfemoral approach, 65 with transfemoral surgical cutdown, and 32 with a non-transfemoral approach). Balloon-expandable and self-expanding valves were implanted in 235 and 107 patients, respectively. Platelet counts started to drop immediately, reaching a nadir 2-4 days after TAVI. Clinically significant thrombocytopenia (CSTP) was defined as a platelet count ≤50×10⁹/L at the time of the nadir or both a platelet count between 80 and 51×10⁹/L and a decrease in platelet count ≥50%. CSTP occurred in 16.7% patients. Approach site and TAVI valve selection significantly predicted CSTP. In multivariate analysis, independent predictors of CSTP were liver cirrhosis (odds ratio [OR] 7.22; 95% confidence interval [CI] 1.05-49.82), baseline platelet count ≤120×10⁹/L (OR 2.98; 95% CI 1.20-7.38), multiple blood transfusions (OR 4.03; 95% CI 1.72-9.41), and the use of balloon-expandable valves (OR 2.38; 95% CI 1.04-5.46). Kaplan-Meier survival analysis with a generalized Wilcoxon test revealed that mid-term (2 years) mortality was greater for patients with than without CSTP (31.4% vs. 15.5%; P=0.008).

CONCLUSIONS

TAVI-related CSTP was not rare and was associated with poor mid-term outcomes. CSTP was not only caused by patients' comorbidities and TAVI complications, but also related to TAVI procedural factors.

Between a Rock and a Hard Place: How to Use Antithrombotics in Patients Undergoing Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has become the preferred method for management of severe aortic stenosis in patients who are at high and intermediate surgical risk, and has recently gained approval from the Food and Drug Administration in the US for use in patients at low risk for surgery. Thrombocytopenia and thromboembolic events in patients undergoing TAVR is associated with increased morbidity and mortality, and yet there is insufficient evidence supporting the current guideline-mediated therapy for antithrombotics post-TAVR. In this article, the authors review current guidelines for antithrombotic therapy in patients undergoing TAVR, studies evaluating antiplatelet regimens, and studies evaluating the use of platelet function testing after TAVR. They also offer a potential link between thrombocytopenia and antiplatelet treatments in patients undergoing TAVR.

Blood Disorders in Patients Undergoing Transcatheter Aortic Valve Replacement: A Review

Transcatheter aortic valve replacement (TAVR) is well established for treating patients with severe aortic stenosis considered at intermediate to high surgical risk. Blood disorders such as anemia, thrombocytopenia, and acquired type 2A von Willebrand disease are relatively frequent in TAVR candidates, and multiple studies to date have highlighted their potential clinical association with mortality and/or bleeding complications post-TAVR. The present review provides an overview of various blood disorders observed pre- and post-TAVR, with special focus on their incidence, etiology, clinical association, and management.

Effect on Mortality of Systemic Thromboinflammatory Response After Transcatheter Aortic Valve Implantation

After transcatheter aortic valve implantation (TAVI) there is consistently identified decrease in platelets accompanied by a leucocyte (white blood cell, WBC) increase. We aimed to analyze the prognostic value of early platelet and WBC count changes (thromboinflammatory response) after successful TAVI. Among 432 consecutive patients [median 83.0 years of age, 63.4% women], platelets and WBCs were measured before and for 7 days post-TAVI. Follow-up was 36.9 (21.4 to 48.0) months. Platelet decrease (∆%Platelet-max) and parallel WBC increase (∆%WBC-max) were seen at days 1 to 3. Both ∆%Platelet-max ≤-37.6% and ∆%WBC-max >72.5% predicted mortality (area under the curve = 0.569 and area under the curve = 0.626). The 30-day and 1-year mortality (13.1% and 26.2%) were highest among 28% patients with a greater decrease in platelets and a greater increase in WBCs; intermediate (0.9% and 12.3%) among 52.5% patients with either a greater decrease in platelets or a greater increase in WBCs, but not both; and lowest (0% and 6.6%) among 19.5% patients with a lesser decrease in platelets and a lesser increase in WBCs (p <0.001). Estimated 4-year mortality rates were 53.7% versus 36.2% versus 24.5%, respectively, p <0.001. Bleeding, surgical wounds, acute kidney, and brain injury predicted a more intense thromboinflammatory response, whereas use of the newer generations had the opposite effect. In conclusion, substantial thromboinflammatory response identified after successful TAVI predicts a higher long-term mortality.

Clopidogrel pretreatment may reduce early acquired thrombocytopenia after transcatheter aortic valve replacement (TAVR)

Transcatheter aortic valve replacement (TAVR) causes early acquired thrombocytopenia on postoperative Days 1 and 2 in 30-50% of patients. While usually transient and rarely severe, early acquired thrombocytopenia is strongly associated with 30-day and 1-year post-TAVR outcomes, including mortality. Observation from a prospective registry suggests pretreatment with the P2Y₁₂ receptor inhibitor clopidogrel before TAVR reduces the frequency and magnitude of early acquired thrombocytopenia. If a protective effect of clopidogrel pretreatment on early thrombocytopenia can be confirmed, then further study to determine if this translates into improved TAVR outcomes is warranted.

Impact of chronic thrombocytopenia on in-hospital outcomes and healthcare resource utilization after transcatheter aortic valve replacement

BACKGROUND

There is little data on the impact of chronic thrombocytopenia (CTP) on outcomes after transcatheter aortic valve repair (TAVR). Most studies are from single centers and mostly focused on postprocedure thrombocytopenia.

OBJECTIVES

This study sought to report on the impact of CTP (>1 year) on in-hospital outcomes and healthcare resource utilization after TAVR.

METHODS

From the National Inpatient Sample (NIS) between 2012 and 2015, we identified patients with CTP who underwent TAVR. A 1:1 propensity-matched cohort was created to examine in-hospital outcomes in patients with and without CTP. The primary outcome was in-hospital mortality. Secondary outcomes included postprocedure complications, length of stay, total cost, and discharge disposition.

RESULTS

A matched pair of 4,300 patients with and without CTP were identified. Patients with CTP had higher in-hospital mortality as compared to no CTP patients (6.0 vs. 3.3%, p-value .007), increased postprocedure hemorrhage, platelet and blood transfusion, vascular complications, postop sepsis, and acute kidney injury. With regards to resource utilization, CTP patients had a longer length of stay, higher total cost and were more likely to be discharged to a facility (34.1 vs. 27.6%) other than home (All, p-value <.001). Subanalysis, however, revealed this difference in resource utilization was seen when patients developed postprocedure complications.

CONCLUSION

This study demonstrated higher risk of in-hospital mortality, perioperative complications, and healthcare resource utilization in patients with baseline CTP undergoing TAVR. Further studies are required to investigate ways to improve the management of these patients.

In-Hospital Outcomes After Transcatheter Aortic Valve Implantation in Patients With Versus Without Chronic Thrombocytopenia

Patients with chronic thrombocytopenia (cTCP) were excluded from the pivotal transcatheter aortic valve implantation (TAVI) trials. The National Inpatient Sample was queried and propensity score matching was performed to evaluate the prevalence and impact of cTCP on in-hospital clinical outcomes after TAVI. The main outcome was in-hospital mortality in patients with versus without cTCP. Among 38,855 TAVI hospitalizations, 7,105 had a diagnosis of cTCP (18.3%). In-hospital mortality was similar in both groups (OR_adjusted 0.79; 95% confidence interval [CI] 0.57 to 1.09); however, cTCP was associated with higher risk of acute kidney injury (OR_adjusted 1.29; 95% CI 1.08 to 1.54), vascular complications (OR_adjusted 1.99; 95% CI 1.22 to 3.25), perioperative blood product transfusion (OR_adjusted 1.69; 95% CI 1.42 to 2.01), cardiac tamponade (OR_adjusted 4.04; 95% CI 1.51 to 10.82), cardiogenic shock (OR_adjusted 1.52; 95% CI 1.07 to 2.15), and use of extracorporeal membrane oxygenation (OR_adjusted 2.32; 95% CI 1.1 to 4.9). In conclusion, cTCP is common in patients who underwent TAVI and is associated with worse postprocedure clinical outcomes, however, with similar in-hospital mortality.

Peri-procedural thrombocytopenia after aortic bioprosthesis implant: A systematic review and meta-analysis comparison among conventional, stentless, rapid-deployment, and transcatheter valves

BACKGROUND

Thrombocytopenia has been shown to occur soon after surgical biological aortic valve replacement (AVR), and recently reported also after transcatheter valve implantation (TAVI). The mechanism underlying this phenomenon is still unknown, and its clinical impact on the peri-operative outcome has been poorly investigated.

METHODS

A systematic review and a meta-analysis of all available studies reporting data about peri-procedural thrombocytopenia on isolated bio-AVR, comparing rapid-deployment (RDV), stentless (stentless-AVR), and TAVI vs. stented (stented-AVR) valves, have been performed.

RESULTS

Fifteen trials (2.163 patients) were included in the meta-analysis. Perioperative platelet reduction ranged from 35% to 55% in stented-AVR, from 60% to 77% in stentless-AVR, from 53% to 60% in RDV, and from to 21% to 72% in TAVI (apparently, balloon-expandable valves more frequently associated to thrombocytopenia). Stented-AVR required more red blood cells transfusion than stentless-AVR (P < 0.0001), whereas no difference has been found between RDV and stented-AVR. Platelet transfusion rate was very low in all surgical groups. No difference has been found in RDV and stentless-AVR vs. stented-AVR, in terms of reoperation for bleeding, and length-of-intensive care unit or hospital stay.

CONCLUSIONS

Thrombocytopenia-related major adverse events were mainly reported in TAVI patients, whereas clinically meaningless in surgical patients. Transient peri-procedural thrombocytopenia is common after bio-AVR, regardless of prosthesis's type or implant modality. It should receive appropriate monitoring and focused investigations.

Changes in thromboinflammatory profiles across the generations of transcatheter aortic heart valves

The transcatheter aortic valve replacement (TAVR) procedure was developed to provide patients with severe aortic stenosis an alternative to the surgical aortic valve replacement. Since the approval of the original SAPIEN the technology has rapidly evolved. While several approaches can be used for valve deployment, as delivery systems have become smaller and more flexible, the transfemoral approach has become the dominant technique for valve deployment. One hundred and forty five patients undergoing TAVR receiving one of four valve types (Sapien, Sapien XT, Sapien3 or CoreValve) via the femoral artery were included in this study. Platelet count, white blood cells count (WBC), Interleukin-6 (IL-6), and Serum Amyloid A (SAA) were determined before and after TAVR. Platelet counts declined after the procedure regardless of the valve type and were dependent upon the baseline platelet count. Use of conscious sedation blunted the decline in platelet count. With the newer generation valves, the rise in WBC post-TAVR was lower than observed with the Sapien, in keeping with less systemic inflammation. Consistent with WBC, IL-6 levels were lower following deployment of the newer generation valves. Elevations in plasma SAA, which occur following myocardial injury, were not reduced with the newer valves. Evolution of the TAVR technology has occurred rapidly over the last 5 years. The newer devices and smaller delivery systems are associated with less systemic inflammation, as reflected in WBC and plasma IL-6 levels. However, the acute phase reactant SAA remains unchanged, possibly reflecting different triggers for SAA following TAVR.

Thrombocytopenia after transcatheter aortic valve replacement: What is really going on?

In a multivariate model, the drop-in platelet count (DPC) was significantly higher in patients treated with a balloon expandable valve (BEV) than a self-expandable valve (SEV) (36.3% ± 15.1% vs. 27.7% ± 14.4%, p < .001). In a univariate model, a higher DPC post-transcatheter aortic valve replacement was observed in patients requiring alternate access and lower contrast volume. The platelet count nadir was nearly a day later in patients implanted with a BEV compared with an SEV. At 30 days, there was a higher rate of adverse events and mortality in patients with a high DPC. At 1 year, there was no significant difference in mortality rates between the high DPC group and the low DPC group.

Preprocedural P2Y12 inhibition and decrease in platelet count following transcatheter aortic valve replacement

BACKGROUND

Thrombocytopenia after transcatheter aortic valve replacement (TAVR) is associated with adverse clinical outcomes. Whether preprocedural P2Y₁₂ inhibition prevents postprocedural thrombocytopenia is uncertain.

METHODS

This retrospective analysis identified consecutive patients (n = 266) undergoing TAVR between November 2016 and July 2017. Preprocedure clopidogrel load ≥300 mg or maintenance P2Y₁₂ inhibitor therapy defined preprocedural P2Y₁₂ inhibition. Patients who did not consent for the registry (n = 8), with baseline severe thrombocytopenia (<90 × 10³  platelets/μL; n = 14), or without baseline platelet count (n = 4) were excluded. The primary outcome was proportion of patients who developed >20% decrease in platelet count from baseline to day 1 post-TAVR.

RESULTS

Patients with (n = 134) versus without (n = 106) preprocedural P2Y₁₂ inhibition had no differences in platelet count at baseline. Patients with preprocedural P2Y₁₂ inhibition had a significantly lower proportion of the primary outcome (34.3% vs. 57.5%, p = .001) and a lower absolute decrease in platelet count (32.8 × 10³ vs. 45.8 × 10³  platelet/μL, p = .01). Of patients without baseline thrombocytopenia (n = 198), a numerically lower rate of patients with versus without preprocedural P2Y₁₂ inhibition developed thrombocytopenia on day 1 post-TAVR (25.5% vs. 36.4%, p = .1).

CONCLUSION

Patients who received preprocedural P2Y₁₂ inhibition prior to TAVR were less likely to demonstrate a decrease in platelet count after TAVR. Prospective studies to further understand the clinical implication of these findings are warranted.

Reduction in thrombogenic activity and thrombocytopenia after transcatheter aortic valve implantation - The ATTRACTIVE-TTAS study

Introduction

Bleeding complications after transcatheter aortic valve implantation (TAVI) is a major problem in clinical practice. However, there is few information on thrombogenicity after TAVI. The aim of this study was to establish a monitoring of total thrombogenicity in perioperative TAVI using the Total Thrombus-formation Analysis System (T-TAS), a microchip-based flow chamber system for analysis of thrombus formation under flow condition.

Methods

Twenty-three patients with severe aortic stenosis who underwent TAVI between August 2017 and March 2018 at Kumamoto university hospital were enrolled. After exclusion, data of 21 patients were analyzed. Blood samples were obtained before, 2, 7, and 30 days after TAVI. Thrombogenicity were assessed by the T-TAS to compute the area under the curve (AUC) (AR₁₀-AUC₃₀) in the AR chip. We also measured platelet count, high-molecular-weight von Willebrand factor (HMW-vWF) multimers, and plasma thrombopoietin. Computational fluid dynamics (CFD) analysis was performed to calculate the wall shear stress (WSS).

Results

The AR₁₀-AUC₃₀ levels and platelet counts were significantly lower at 2 days post-TAVI, and then increased gradually. HMW-vWF multimers, and plasma thrombopoietin, were significantly higher at 2 days post-TAVI, compared with before TAVI. CFD analysis showed that WSS of the aortic valve and posterior ascending aortic wall were significantly lower after TAVI than before-TAVI. Multivariate analysis identified max velocity measured by echocardiography, platelet count, and D-dimer as significant determinants of AR₁₀-AUC₃₀, representing total thrombogenicity.

Conclusions

Although HMW-vWF multimers improved earlier after TAVI, total thrombogenic activity evaluated by T-TAS remained relatively low followed by improvement in thrombogenic activity at 30 days after TAVI.Clinical Trial Registration: https://clinicaltrials.gov. Unique identifiers: NCT03248232.

Comparison of the Frequency of Thrombocytopenia After Transfemoral Transcatheter Aortic Valve Implantation Between Balloon-Expandable and Self-Expanding Valves

Thrombocytopenia after transcatheter aortic valve implantation (TAVI) is common and has been related to worse clinical outcomes. Comparison of platelet kinetics among different types of valves is limited. Our objectives were to analyze the differences in drop platelet count (DPC) between balloon-expandable valves (BEVs) and self-expanding valves and their prognostic implications after TAVI. Patients who underwent transfemoral TAVI from 2008 to 2016 were included. Exclusion criteria were severe baseline thrombocytopenia and periprocedural death. Postprocedural platelet counts were collected. Two groups were created: DPC ≤30 and DPC >30%. Valve Academic Research Consortium-2 criteria were used to define outcomes. Study population included 609 patients (age 84.7 ± 6.0, 46.6% males). The mean DPC was 32.5 ± 13.9%. The DPC was higher in the BEV arm (33.9 ± 14.2 vs 30.7 ± 13.4%, p = 0.006), and the nadir was reached later in comparison to the self-expanding valve arm (3.0 ± 1.3 vs 2.5 ± 1.1 days, p <0.001). After multivariable analysis, the use of BEV, known coronary artery disease, and left ventricle ejection fraction were the factors associated with a higher rate of DPC >30%. At 30 days, the DPC >30% was related with a higher rate of life-threatening and/or major bleeding (6.8 vs 2.1%, p = 0.009) and death (3.5 vs 0.8%, p = 0.036). At 1 year, the difference in mortality disappeared. In conclusion, in this cohort of patients, the use of BEV seems to be associated with a higher risk of DPC after TAVI. A DPC ≥30% was related with increased risk of life-threatening and/or major bleeding and death at 30 days. Larger and prospective studies are needed to understand this phenomenon.

Thrombocytopenia After Transcatheter Valve-in-Valve Implantation: Prognostic Marker or Mere Finding?

Objective

To analyze the behavior of platelets after transcatheter valve-in-valve implantation for the treatment of degenerated bioprosthesis and how they correlate with adverse events upon follow-up.

Methods

Retrospective analysis of 28 patients who received a valve-in-valve implant, 5 in aortic, 18 in mitral and 5 in tricuspid positions. Data were compared with 74 patients submitted to conventional redo valvular replacements during the same period, and both groups' platelet curves were analyzed. Statistical analysis was conducted using the IBM SPSS Statistics(r) 20 for Windows.

Results

All patients in the valve-in-valve group developed thrombocytopenia, 25% presenting mild (<150.000/µL), 54% moderate (<100.000/µL) and 21% severe (<50.000/µL) thrombocytopenia. The platelet nadir was on the 4^th postoperative day for aortic ViV, 2^nd for mitral and 3^rd for tricuspid patients, with the majority of patients recovering regular platelet count. However, the aortic subgroup comparison between valve-in-valve and conventional surgery showed a statistically significant difference from the 7^th day onwards, where valve-in-valve patients had more severe and longer lasting thrombocytopenia. This, however, did not translate into a higher postoperative risk. In our study population, postoperative thrombocytopenia did not correlate with greater occurrence of adverse outcomes and only normal preoperative platelet count could significantly predict a postoperative drop >50%.

Conclusion

Although thrombocytopenia is an extremely common finding after valve-in-valve procedures, the degree of platelet count drop did not correlate with greater incidence of postoperative adverse outcomes in our study population.

Concurrent mechanical haemolytic anaemia and heparin-induced thrombocytopenia following transcatheter aortic valve replacement

A 78-year-old man with a history of severe aortic stenosis presented with confusion, irregular behaviour and dyspnoea 8 days following transcatheter aortic valve replacement. His exam was consistent with a heart failure exacerbation and he had elevated aminotransferases, bilirubin and prothrombin time suggestive of shock liver. A CT head scan demonstrated a subacute large left temporoparietal infarction. His aminotransferase and prothrombin time levels normalised with diuresis, but his indirect bilirubin remained elevated and he developed anaemia and thrombocytopenia consistent with a haemolytic anaemia. A transthoracic echocardiogram demonstrated a paravalvular leak. His thrombocytopenia continued to worsen prompting testing for antibodies against heparin-PF4 complexes which was positive. A serotonin release assay later returned positive, confirming the diagnosis of heparin-induced thrombocytopenia. This case illustrates that the presence of haemolytic anaemia does not necessarily exclude other causes of thrombocytopenia that may occur concurrently.

Thrombocytopenia after transcatheter aortic valve implantation. A comparison between balloon-expandable and self-expanding valves

BACKGROUND

Thrombocytopenia after transcatheter aortic valve implantation (TAVI) is common and has been related to higher mortality and major complications. No comparison between balloon-expandable (BEV) and self-expanding valves (SEV) regarding drop platelet count (DPC) has been reported to date. The objectives of this study were to analyze the differences in DPC between BEVs or SEVs and their prognostic implications in clinical outcomes.

METHODS

We retrospectively analyzed patients undergoing TAVI. Platelet counts after TAVI were collected. Two groups were created: DPC ≤ 30% and DPC > 30%. VARC-2 criteria were used to define outcomes.

RESULTS

Study population was composed of 195 patients (age 77.5 ± 6.7, 57.4% males). All of them but one experienced DPC (mean DPC 31.9 ± 15.3%). DPC was significantly higher among the patients treated with BEV compared to those treated with SEV (36.3 ± 15.1% vs 27.7 ± 14.4, P < 0.001). After multivariate analysis, the use of BEV was independently associated with a higher rate of DPC > 30% (67.4% vs 36.0%; OR 3.4; 95% CI, 1.42-8.16). At 30 days, the DPC > 30% was associated with a higher rate of life-threatening/major bleeding, major vascular complications, in-hospital sepsis and mortality. At one year, there were no statistically significant differences in the mortality rate between groups (6.35% vs 10.0%, HR 1.54; 95% CI, 0.56-4.25).

CONCLUSIONS

In this study, the use of BEV was associated with a higher risk of DPC after TAVI. A DPC rate > 30% was associated with an increased risk of major complications at 30 days.

Von Willebrand factor and the aortic valve: Concepts that are important in the transcatheter aortic valve replacement era

Since the approval of the first transcatheter aortic valve replacement (TAVR) device in 2011, this technology has undergone substantial enhancements and exponential growth. However, valve thrombosis and residual paravalvular leaks (PVL) are among the challenges that require further investigation. Recently, monitoring von Willebrand factor (vWF) multimers has emerged as a tool to help evaluate the severity of PVL after TAVR. Following TAVR, vWF large multimers recovery have been documented. The role of large vWF multimers recovery and their interactions with platelets, and the endothelium have not been entirely elucidated. In this review, we discuss vWF synthesis and its role in aortic stenosis. We further provide an overview of the studies that investigated changes affecting vWF multimers following TAVR and the role of HMW vWF multimers monitoring in the determination of PVL severity. We also offer potential future directions for what will be fertile ground for research in this field.